


Human Calculus

by nagi_schwarz



Series: Prompt Fills 2018 [32]
Category: Stargate Atlantis
Genre: Bodyswap, Light Angst, M/M
Language: English
Status: Completed
Published: 2018-06-08
Updated: 2018-06-08
Packaged: 2019-05-19 17:48:59
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,036
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/14878446
Author URL: https://archiveofourown.org/users/nagi_schwarz/pseuds/nagi_schwarz
Summary: Written for the numbers comment_fic prompt: "Stargate Atlantis, John Sheppard/Rodney McKay, math had always been the easiest thing in the world."Math is easy for John because he sees the world in numbers, for better or for worse. For worse for Rodney, when Rodney ends up in his body.





	Human Calculus

Math had always been the easiest thing in the world for John, he said. Easier than talking to people or being charming or even flying a chopper. Rodney understood that, he thought. Music hadn’t been easy for Rodney, though he’d worked doggedly to attain the technical skill he needed to perform complex pieces. But physics - that always been easy for Rodney. Understanding certain parts of the universe, forces and movement and wave harmonics, light and motion and sound, how it all fit together - Rodney had always understand that.  
  
So he figured he understood what John meant when John said math had always been the easiest thing in the world.  
  
And then they went offworld and touched the wrong Ancient device at the same time and ended up in each other’s bodies.  
  
Miko, Radek, and every other scientist with even any remote knowledge of Ancient tech and biology and physiology was sent to tackle the problem, some to examine the device, others to examine John and Rodney.  
  
While Rodney had always been attracted to John, he wasn’t about to violate the man’s privacy, and he didn’t want John to figure out Rodney was attracted to him while he was in Rodney’s body, so he wanted the situation fixed as soon as possible. At first he thought it’d be fun, being in better shape, being handsome. John disliked being in Rodney’s body - he missed orange juice and his back hurt all the time and when he got hungry, he turned mean and got headaches.  
  
“It explains so much about you,” John said over lunch, where he was eating twice as much as Rodney normally did.  
  
Rodney was enjoying orange juice while he could.  
  
“Honestly,” John said, “given how awful you feel all the time, I’m surprised you’re not crankier.”  
  
“Thanks,” Rodney said flatly.  
  
Just when he thought things couldn’t get worse - John hated his body, hated  _him_  - Lorne approached them and suggested, very quietly, that maybe they attempt to reverse the process themselves.  
  
“We already tried. Poked the device a bunch of times,” Rodney said. “Nothing works.”  
  
Lorne cleared his throat. “Back at the SGC, there was precedent for you two reversing the process yourselves by, you know, commingling. In this state.”  
  
John stared at him. Was that what Rodney looked like when he was unimpressed? No wonder he hadn’t dated a woman in forever. “You’re going to have to be a bit blunter, Major.”  
  
Lorne blushed bright pink, and Rodney realized what he meant. He wouldn’t have been opposed to that, but judging by the look on John’s face once he also caught on to the implication, he was very opposed to that option.  
  
Lorne turned and scurried away without saying another word.  
  
“I’m sure Miko and Radek and the others will figure something out,” John said stiffly.  
  
“Yeah. We can wait,” Rodney said.  
  
Turned out he couldn’t, though.  
  
Because John’s head was filled with math all the time. John was so effortlessly good at math because existence was math to him. Time, crunched down into minutes and seconds and microseconds. Firearm accuracy, calculated to minute of angle in an instant. And endless, endless probabilities. Rodney in John’s body watched Lorne speed by on his morning run and he knew Lorne was only running at eighty percent efficiency, that he was still getting over a cold, and that Lorne and his team’s scheduled mission today had a mortality rate of about forty percent, but that number steadily ticked upward as John assessed each team member’s condition.  
  
John’s head was screaming with probabilities and possibilities when Rodney watched Lorne’s team go through the gate.  
  
And John’s head was filled with the same probabilities and possibilities every time he encountered someone.   
  
How John ever agreed to let anyone go through the gate was a total mystery.  
  
Math was easy for John.  
  
Living with it was impossible for Rodney.  
  
After a mere fifty hours - not even two full Lantean days - Rodney cornered John.

“We should try the thing that Lorne suggested. To change back.”  
  
“Why?”  
  
“Please,” Rodney said.  
  
John looked terribly discomfited. “But Radek and the others are working hard.”  
  
Rodney took a deep breath. “It’s - the math. I can’t handle it anymore.”  
  
John cocked his head, looked puzzled. “What? Why? You’re capable of high-level math.”  
  
“That’s not what I’m talking about.”  
  
“Then what  _are_  you talking about?”  
  
“I’m talking about how you know every second of every day what chances people have of surviving - everything.”  
  
John still looked confused.  
  
Rodney rocked back on his heels. “You don’t even realize you do it.” Rodney looked at John, at his own body, and wondered what it was John saw in him.  
  
An appallingly low survival rate for most combat disasters, as it turned out.  
  
But Rodney also felt a familiar flare of desire. John was  _attracted_  to him.  
  
Rodney stepped closer to him. “John, please. You want your body back. As weak and pathetic as my body is, it’s  _mine,_ and I want it back too. Can we just - try?”  
  
No, John’s brain screamed. It calculated shifts in hormone levels in an instant. John couldn’t sleep with Rodney just once and walk away from it. He’d be hooked forever. That flood of oxytocin and dopamine, coupled with Rodney in his in his bed, in his arms, in his  _body_  (oh hey, John liked to bottom?) and John would never be able to look at Rodney the same.  
  
“Please,” Rodney said again. He didn’t say it often. “Come on.” Then he took a deep breath and added, “It doesn’t have to just be the once.”  
  
John took a step back, and Rodney recognized that expression on his own face - defensiveness.  
  
“After we change back, we can do it the right way. As ourselves.”  
  
John looked pained.   
  
Rodney, against all the screaming numbers and probabilities and statistics, said, “John, I’m in love with you.  _Please.”_  
  
And John kissed him.  
  
Afterwards, blissfully post-orgasm and back in their own bodies, John said, “I like your body, by the way. It - being in your body isn’t easy. But I like it. A lot.”  
  
“Thanks,” Rodney said. “Your body is pretty fantastic too.”  
  
But he hoped he never saw the inside of John’s mind like that again.


End file.
